This invention relates to a mirror and an angle detection apparatus therefor.
A mirror angle detection apparatus having a magnet fixed on a plate pivot (pivot table) of a mirror assembly and a magnetism sensor provided in an angle changing actuator assembly is known in the art (see Japanese Utility Model Application, Laid-Open No. 3-112441 U). The magnetism sensor or magnetism sensing element used therein detects a variation in magnetic field resulting from inclination or angular displacement of a specular surface of the mirror assembly.
In this conventional construction, however, in order to detect a whole range of angular displacement of the specular surface using the magnet fixed on the plate pivot, the size of the magnet to be used should be large enough to cover the movement of the plate pivot. Further, in order to appropriately detect a variation in magnetic field resulting from the inclination of the specular surface, for example as shown in FIG. 5, the center of rotation of the plate pivot, the magnet and the neutral position of the magnetism sensing element should be arranged in proper alignment along one and the same line. This would impose a restriction in layout, and thus affect space efficiency in some instances, in designing a mirror with angle detection capability. In actuality, effective use of space would be greatly desired for example in an exterior mirror for an automobile in that the space available within the mirror body is limited and at a premium.
In addition, the actuator for tilting the specular surface should be selected from those designed specifically for angle detection, which would thus only be available with angle detection apparatus, and cost-effective general-purpose actuators would not be applicable. Moreover, in most cases, particularly where a special wiring arrangement such as a harness is provided to establish connection from a substrate to the magnetism sensing element disposed near the magnet, such a complicate construction would impair the workability of wiring, and thus increase the manufacturing cost.
Under the circumstances, it would be desirable to provide a mirror and an angle detection apparatus therefor in which the above-described disadvantages are eliminated.
Illustrative, non-limiting embodiments of the present invention overcome the above disadvantages and other disadvantages not described above. Also, the present invention is not required to overcome the disadvantages described above, and an illustrative, non-limiting embodiment of the present invention may not overcome any of the problems described above.